As with most games, Tetris has a lot of casual fans. It's believed that two out of every three Americans have played the game at some point. But few are truly experts. If you've never reached the maximum possible score of 999,999 points, or if you've never reached level 29 (by clearing at least 290 lines, where the blocks are falling so fast that it's believed to be impossible to maneuver them into place quickly enough), then you're just like virtually everyone else on the planet. There are only a couple of people in the world who can claim those accomplishments, and not even some of the super-elite players have achieved those milestones.
Thor Aackerlund is one of the first people to be able to legitimately claim himself to be a Tetris master. He won the 1990 Nintendo World Championship (the same competition featured in the 1989 film The Wizard) where Tetris was the featured game, and he had made some pretty impressive claims about his abilities over the years. But Thor was something of a recluse and never submitted any kind of evidence to back up his statements, so many in the Tetris community were skeptical. Robin Mihara had played against (and lost to) Thor in that tournament, and had spent much of the two subsequent decades wondering who really is the best Tetris player in the nation.
The invitees were the cream of the crop in the Tetris world, many of whom held (at least at one time) some kind of record. This included Jonas Neubauer and Harry Hong, the only players to have confirmed scores of 999,999 points. It also included Ben Mullen and Jesse Kelkar, who had reached level 29. Other top players like Dana Wilcox and Chris Tang were offered slots. And Thor, despite his reluctance to provide evidence to back up his claims of recent exploits, was invited if for no other reason than curiosity among the others.
There are a lot of similarities between Ecstasy of Order and the great Donkey Kong documentary King of Kong: A Fistful of Quarters. However, there are also a lot of differences. While both films focus on people vying for greatness in video games, it's surprising to see the degree of camaraderie among the Tetris players in contrast to the animosity between the Donkey Kong combatants. While most people likely find themselves rooting against Billy Mitchell in King of Kong, I was surprised to find I was rooting for everyone in Ecstasy of Order. The players are absolutely focused on winning, and yet there is a great deal of civility and mutual admiration between them which makes the film a joy to watch.
There is a lot of great content in the interviews with and interactions between the players, but it's also a lot of fun to just watch them play, and there's plenty of that to enjoy. As I learned from the mini Tetris tournament held at the Alamo Drafthouse after the film ended, it's fun to watch even awful players try their luck. It makes the achievements of the top players even more impressive when immediately followed by "regular people" who fail to score any points or complete any lines. It's interesting to see the differences in skills and strategies of the best players in the game, and the differences in personalities and knowledge of the game.
It's hard to say anything bad about Ecstasy of Order, unless perhaps you find yourself frustrated by not having ready access to a quality version of Tetris. But even that's a problem that can be overcome without too much effort or expense.